Screen Size Comparison
Compare viewable area between two diagonals.
Inputs
Loading calculator…
Calculating…
Was this helpful?
Formula
height = diagonal ÷ √(1 + (W/H)²); width = height × (W/H); area = W × H
From each diagonal and a shared aspect ratio, solve for width and height using the Pythagorean theorem, then compare viewable areas in square inches.
Worked example
A 55″ 16:9 TV has about 1,287 sq in of viewable area; a 65″ panel has about 1,792 sq in — roughly 39% more screen, not the 18% you'd guess from diagonal alone.
Where this can give the wrong answer
- Diagonal inches ignore bezels — marketed 'screen size' is viewable panel only.
- Ultrawide monitors need their true aspect ratio (e.g. 21:9), not 16:9.
- Both screens are assumed to share the same aspect ratio; mixing 4:3 and 16:9 needs two separate runs.
FAQ
- Diagonal is a linear measure; area scales with width × height. A larger diagonal grows both dimensions, so area increases faster.